Differentiation in Vitro of Mouse Limb Buds in Some Media

Anterior limb buds from the 11-day-old mouse embryos were cultivated for 24 hours in a chemically defined medium or in chemically defined medium with biologic supplements using the agar culture method for the purpose of comparison among those media.1. In Medium 199, scarcely any growth or histological diff e rentiation was observed.2. It w as revealed that the biologic supplement,, i. e., chick embryo extract or horse serum, was necessary for the development of limb bud and the differentiation of mesenchyme into cartilage.3. The three media, Medium 199 with chick embryo extract, Medium 199 with horse serum and Medium 199 with chick embryo extract and horse serum, gave almost the same results. In the former two media, the differentiation of mesenchyme into cartilage was more advanced, while in the latter media, the digital rays developed more frequently with the thining-out of mesenchyme.